Development and Performance Evaluation of Eco-Friendly Bricks Using Fly Ash, Coconut Shell, and Coconut Fiber- A Review

Abstract- The construction industry is one of the major contributors to environmental degradation due to excessive consumption of natural resources such as clay, sand, and limestone, along with high carbon dioxide emissions from cement manufacturing and brick kiln operations. Conventional fired clay bricks require significant amounts of fertile soil and fuel, leading to depletion of agricultural land and emission of greenhouse gases. In recent years, the utilization of industrial and agricultural waste materials has emerged as a sustainable solution for manufacturing eco-friendly building bricks. Among these waste materials, fly ash, a by-product of thermal power plants, has gained significant attention due to its pozzolanic nature and availability in large quantities. Similarly, coconut shell and coconut fiber, which are agricultural residues, possess favorable properties such as low density, good toughness, and thermal insulation potential. This review paper presents a comprehensive study of the development and performance evaluation of eco-friendly bricks and blocks incorporating fly ash, coconut shell, and coconut fiber. A detailed literature survey of 16 previous research studies has been conducted to analyze the influence of these materials on the mechanical properties (compressive strength, tensile strength, flexural strength), physical properties (density, water absorption, porosity), durability behavior (thermal resistance, shrinkage, efflorescence), and sustainability aspects (cost-effectiveness, waste management, carbon reduction). The review indicates that fly ash contributes to strength development and reduced water absorption, coconut shell improves lightweight characteristics, and coconut fiber enhances crack resistance and ductility. However, challenges such as reduction in workability, increased water absorption due to fiber inclusion, and lack of standard mix design guidelines still exist. Based on the critical analysis, significant research gaps have been identified, particularly regarding optimization of mix proportions, performance evaluation under long-term durability conditions, and standardization of eco-friendly brick manufacturing procedures. The paper concludes that fly ash, coconut shell, and coconut fiber-based bricks can serve as promising sustainable alternatives for modern construction, but further experimental validation and field-scale studies are necessary for widespread adoption.